ULOTHRIX 153 
so as to show any particular difference between their chromatophore 
characters. Itisalso generally difficult to find authoritative points 
of separation in the original descriptions of such fine species. 
In the description, however, of U. variabilis, the following 
phrases are used : “ nucleis cellularum quadratis saepius angustis 
pectinatim dispositis " (Kützing, '49). “ Zellinhalt aufangs genau 
quadratisch '' (Rabenhorst, '63), and *' cytioplasmate initio semper 
quadrato-contracto (Rabenhorst, '68). Now the chromatophore 
of the form identified above as this species would hardly be called 
square, but itis generally contracted and placed on one side of the 
cell. Furthermore, so far as one can judge from the illustration 
given by Kützing (52), our specimens conform to his species. 
We believe, therefore, that there is no question as to the cor- 
rectness of the above description for U. variabilis and of the dis- 
tinctness of this form from U. subtilis (= Stichococcus subtilis 
Klerck.). There is certainly no question as to the specific dis- 
tinctness of the two forms above described from that which is 
hereinafter identified as Stzchococeus subtilis. 
Illustrations like that of Wittrock )83( for this species and 
that of Wille ('85) for U. variabilis f. marina, in which the chroma- 
ophore has a homogeneous, square appearance, were undoubtedly 
made from material not well preserved. They show exactly the 
similarity of appearance which is to be found in dried specimens 
of small forms of Ulothrix and Stichococcus. 
a 
ULOTHRIX IMPLEXA (Kütz.) Kütz. Spec. Alg. 349. 1849; Tab. 
Phyc. 2: A. 94. f. 2. 1852. Hauck; Rabenh. Krypt. Flor. 
Deutschl. 2: 440. 1885. Reinbold, Schrift. Nat. Ver. 
Schles.-Holst. 8: 129. 1889. Batters, Trans. Berwick. Nat. 
Club, — (35). 1889. Foslie. Tromso Mus. Aarsh. 13: 143. 
1890. Collins, Bull. Torrey Club, 18: 336. 1891. 
Hormidium implexum Kitz. Bot. Zeitung, 5: 177. 1847. 
Ulothrix Ligustica Dufour, Erb. Critt. Ital. I. 7052 (fide De 
Toni). 
Bangia ? confervoides Zanard. Atti R. Ist. Ven. 6: 249. pl. 2. 
1847. 
Ulothrix ? confervoides DeToni & Levi, L’Algarium Zanardini, 
134. 1888. 
